Can information like a signature, secret key or password be encoded in a photo?

Question

I want to protect copyright of my photographs. So, I've decided I'd like to put some signature like information in my photos.

According to my research, - I have copyright as default and I don't need to do anything according to most countries' laws. - There are online services where I can register my photos. - And of course I can put watermarks on photos

The watermark option isn't a solution for me because my photos will be printed in books. So I need to share my raw photos with the publisher's partner company whom I don't trust.

The tricky part of my question start here; The paranoiac side of me says that they can steal and use my photos, say on the web, with out my permissions.

Anyway, I thought that if I could put some information (i.e. signature-like specific key) in my photo meta data or pixels (not sure this is possible) which can't be deleted later (better if it's not detectable by others) and I can trace/find my photos with search engines easily.

Is there any way to put such information in to achieve my goal ? Or are there any other methods for this purpose ?

Answer 1

What you are describing is digital watermarking. This isn't the same as traditional watermarking where the watermark is clearly visible, but rather is a way to encode information in to the storage of a photo in which it is difficult to detect and remove. It's not a perfect science and certain types of compression will frequently destroy many digital watermarks, but searching for more information on digital watermarks will yield the best results you will get. Unfortunately, it's a frequently changing field, so I can't really give any specific examples in an answer without making it really time sensitive.

It is worth noting that these won't phone home or anything, but they may let you prove that a photo came from you beyond simply being able to compare the photos and go... see, it's my photo.

Answer 2

Steganography is the study and practice of hiding information. According to the linked article, digital information hidden in files such as photographs is often lost during printing, so that's going to be a hurdle for you if you want to prove that a particular photo is yours.

One technique that could work is a version of the way art is authenticated at least according to the movie The Thomas Crown Affair. In the movie, we're told that museums always keep photos of the borders of paintings, which are normally hidden by the frame. These hidden parts aren't visible to the public, so copies are missing that information. Along those lines, an option might be to give the publisher only part of the original image: either a slightly lower resolution image than the original, or an image that you've cropped slightly.

The best option, I think, is to deal with people you can trust or to get a good lawyer who will protect your interests.

Answer 3

Digital watermarks do exist and they are what you are looking for - but they are not the answer to your problem.

You have the copyright and so you can sue them if they do anything with your pictures without permission - in order to make is easier to prove it's your picture you should register your image with the government organization that deals with those things (in the US it's the library of congress) and not with some "online services".

If you go to court and your picture is registered with the correct government organization that's it, you have the proof you need and all that's left is to decide how much they have to pay you - you can easily get a lawyer that will handle this for you for exchange for a percentage of the payment so suing is essentially free.

If the picture is registered with some other organization or on-line service you have to prove that organization is trustworthy, this can be difficult and expensive - you will have to pay quite a bit for a this and you can easily lose.

If you use digital watermarks you're in even bigger problem and you have to prove that your watermark technology is valid - good luck with that.

Answer 4

I would not bother.

Just keep the RAW files or at least keep the higher resolution JPG for yourself. Nobody else can have them, so you can always proove that you are the original photographer. No need to use watermarks for that. Just put your names in the EXIF or IPTC data so you can easily be found for those people who want to contact you.

Just use picture search services like Google or Tineye to look for copies for your photos from time to time. If someone used your photo without your permission, there are 2 possibilities:

1. they are in a country where you could file a lawsuit. Be happy, you can usually settle for a higher fee. If needed, go to court. Get an insurance first :-)

2. they are in a country where it is hard or impossible to file a lawsuit. So then they can take your picture with or without watermark, they just don't care, and you can't do anything about it